Warmth perception is physical, emotional, semantic, and sensorial bond between people and their environments. Warmth is a prominent characteristic of interior architecture and is related to colours and materials. Although the effects of single colours and single materials on warmth have been explored, colours and materials rarely appear alone in interiors and there has been no research on how paired colours and paired materials affect warmth perception in interiors. Therefore, the main aim of this study is to investigate their effects through a seven-point semantic differential scale and open ended questions.192 different participants assessed three different colours (red, white, and green), and their pairs or three different materials (fabric, timber, and plasterboard), and their pairs under controlled conditions. Findings demonstrated that single colours and paired colours both affect warmth perception in interiors. The effects of single colours in interiors are subtle in warmth perception: red is perceived warmer than green and green is perceived warmer than white. All single colours have a moderate level of warmth in interiors as pairs, consequently red (warm colour) appears to increase and white (achromatic colour) appears to decrease the warmth perception of their pairs. Furthermore, as single materials timber and fabric have the same level of warmth and are warmer than plasterboard whereas there is not any difference between pairs. Findings indicated that natural materials are perceived warmer than artificial one.